This application is a competing continuation that seeks to quantify the relations of Alzheimer's disease and Mild Cognitive Impairment (MCI) to their major consequences in a longitudinal study in the general population and to assess the relations of these consequences to a number of disease and individual characteristics in that setting. It is motivated by expected strong growth in the numbers of persons affected by Alzheimer's disease in the populations of the United States and other developed countries due to rapid increases in size of the oldest age groups, and lack of knowledge about the expected burdens on affected persons, their families, and health-care systems. The proposed study will enroll persons affected by these conditions who have been newly identified by an existing study of risk factors for Alzheimer's disease among residents of a geographically defined biracial urban community, an approach that permits a large-scale, population-based investigation at reasonable cost. Five major consequences are of interest: decline in cognitive function, decline in physical function, nursing-home admission, hospitalization, and mortality. The predictive characteristics of interest are race, age, social variables, behavioral characteristics of the affected person, especially psychotic behavior and depressive symptoms, the APOE epsilon4 allele, education, and presence of sub-clinical infarcts on MRI. We propose to study 850 persons randomly selected from the community population, 423 of whom are already enrolled plus an additional 427 to be enrolled. We estimate that, of these 850 persons, 306 will be affected by incident Alzheimer's disease, 295 will be affected by MCI, and 251 will be cognitively normal persons of similar age. The proposed study will pay special attention to potentially modifiable predictors of consequences and to identifying the time points in the course most susceptible to intervention.